Essential Skills for Scientists 2: Abstracts and summaries in a scientific paper

While marking a set of 127 student papers each containing a summary for “formative” feedback, I realised they need more guidance. The most common comment I made was to tell them to remove “I”, “me”, “my” from this type of writing. That part is easy to solve. The structure and content of a good abstract is more difficult. I have written previously about this, but there is still more to go. 

What is needed in a good scientific summary or abstract? This varies. At the undergraduate level abstracts usually need context and the more routine the analysis, the more important the presentation of the context. Within the set of papers I marked, many students wanted to measure things like fluoride, or sodium, or potassium. They selected a sample to analyse, but rarely indicated why. Consider cocoa. It turns out that cocoa contains potassium and is one of the richest dietary sources known. An assignment covering this topic should begin with something about potassium and cocoa. Potassium is a key element of diet and essential to maintaining a proper electrolyte balance. Many diets contain excessive sodium and less potassium. Cocoa powder has been reported to contain up to 4.5% potassium.

Does this context raise your interest more than a discussion of the operation of a high performance liquid chromatography column? Context will engage your reader more than will a typical approach which might be like this: “This experiment will measure fluoride with an ion selective electrode machine. A set of standards will be prepared...” Somewhere toward the end a sample will be mentioned, but the reader has lost interest. Those still reading are likely wondering, to quote my PhD supervisor, “who the hell cares?” (Read properly that should be yelled using a strong Texas accent.)

Having established the context, your reader will be ready for more. When you continue, explain the study’s goal of sampling commercially available cocoa powders and measuring potassium content using flame photometry (or ion chromatography, or inductively coupled plasma atomic emission spectroscopy, or...). Your audience is prepared. 

Finish an abstract with the results and a conclusion. If you do this well, your reader will know the what, why, and how of your study as well as the results. 

Let’s see how this fits together.

Abstract: Potassium is a required nutrient and essential for maintaining a proper electrolyte balance. Many diets contain excessive sodium and insufficient potassium leading to a need to monitor dietary intake of these elements. Cocoa powder is one of the richest sources of potassium containing up to 4.5% by weight, however, little is known about variability between commercially available brands. This project sampled commercially available cocoa powders and assessed the potassium content using flame photometry following a dry ash procedure. The samples contained between 1.03% and 1.32% K by weight. Replicate analyses indicated the precision of the method was ±0.04% indicating significant differences in potassium content between brands. These results confirmed that, despite the observed variability between brands, cocoa powder is an excellent source of potassium. 

Note: The study and results provided are fictitious. Interested readers wanting to know more about potassium in cocoa powder should go here.